Look at the words carefully, as the slightest mistake can lead to a huge error. Don't be confused by similar words.

Similar words are often seen in a large number of popular health science articles. The general public often misunderstands them, making small mistakes and leading to huge errors. Even professionals may use the wrong words.

1. Incidence and prevalence

Incidence ≠ Prevalence

The incidence rate represents the ratio of the number of new cases of a disease in a certain year (period) to the number of exposed population in the same year (period), and the unit is x/100,000 or a few thousandths.

The prevalence rate indicates the ratio of the number of cases of a disease in a certain period of time to the average population during the same period, and the unit is a few thousandths or x/100,000.

2. Mortality and case fatality rate

Mortality rate ≠ case fatality rate.

The mortality rate represents the ratio of the number of deaths due to a certain disease in a certain year to the average population in the same year, and the unit is x/100,000.

The case fatality rate represents the ratio of the number of deaths from a certain disease in a certain period (usually one year) to the number of patients suffering from the disease in the same period, and the unit is x% or a few thousandths.

3. Thrombosis and embolism

Thrombosis ≠ embolism.

Thrombi are emboli that form "locally".

An embolism is a blockage formed "from outside" that occurs here.

4. Aneurysms and tumors

Aneurysm ≠ tumor.

An aneurysm is a bulge in an artery that resembles a tumor, but it is not a tumor in nature.

5. Reference value and normal value

Reference value ≠ normal value.

Everyone’s examination data is like a tree branch. It is impossible for them to be exactly the same. It is just a matter of probability of being normal or abnormal. There is no normal value.

6. Sensitivity and specificity

Sensitivity ≠ specificity.

Sensitivity: a positive person is not necessarily sick; specificity: a negative person is not necessarily normal.

For tests with high sensitivity, those with negative results are mostly non-patients; for tests with high specificity, those with positive results are mostly patients.

7. Exudate and transudate

Exudate ≠ transudate.

Exudate is caused by inflammation and is commonly seen in tuberculosis, malignant tumors or other causes.

The transudate is caused by high permeability and is commonly caused by heart failure, nephrotic syndrome, portal hypertension or severe edema.

8. Referred pain and rebound pain

Referred pain ≠ rebound pain.

Referred pain originates from the pain impulses of visceral diseases, which can produce pain sensations located on the body surface and often at a distance from the affected organs. The pain sensation is referred to the skin area innervated by the corresponding posterior roots of the spinal cord. The pain impulses can be transmitted through the afferent fibers, causing the excitement of the corresponding spinal segment sensory neurons, resulting in referred pain of varying degrees and ranges. For example, the pain impulses of angina pectoris are transmitted to the thoracic vertebrae 1-2 segment nerves and thoracic vertebrae 3-4 segment nerves, and these nerves innervate pain (behind the sternum, left precordial area, and inner side of the left upper limb).

Rebound tenderness is when the patient feels tenderness when palpating the abdomen with the hand, and then the finger stays in place for a moment, and then the hand is quickly raised. At this time, the patient feels that the abdominal pain is aggravated and has a painful expression. Rebound tenderness is a sign that the peritoneal wall has been affected by inflammation.

9. Cyanosis and hypoxia

Cyanosis ≠ hypoxia.

Cyanosis refers to the phenomenon that the skin and mucous membranes appear bluish purple due to an increase in reduced hemoglobin in the blood. Increased reduced hemoglobin in the blood, coexistence of central and peripheral cyanosis, and abnormal hemoglobin derivatives in the blood can all cause cyanosis, as long as the amount of reduced hemoglobin in capillary blood is greater than 5g/100ml.

10. Dizziness and vertigo

Dizziness ≠ vertigo.

Dizziness is non-rotational, and the patient only feels dizzy, or has abnormal sensations such as black spots in front of the eyes, heavy head and light feet, but there is no sense of rotation of the surrounding scenery. It is commonly caused by organic diseases such as hypertension, cerebral arteriosclerosis or anemia, as well as functional diseases such as neurosis and menopausal syndrome.

Vertigo is rotational and is a movement illusion of spatial positioning. When the eyes are open, there is an illusion that the surrounding scenery is rotating, shaking up and down, or moving left and right, while when the eyes are closed, there is an illusion that one's own rotation or shaking is present. It is often accompanied by nystagmus, imbalance, and symptoms of autonomic nervous system dysfunction such as nausea, vomiting, sweating, bradycardia, and hypotension. It is commonly caused by inner ear labyrinth or vestibular neuropathy.

11. Neurological and mental illness

Neurological disease ≠ mental illness.

Neurological diseases refer to diseases of the central and peripheral nervous systems.

Mental illness often manifests as abnormalities in perception, thinking, emotion, and volitional behavior, and these mental activities are not coordinated, generally without consciousness and intellectual impairment. It is related to factors such as genetics, abnormal neurodevelopment, and quality, and often has abnormal function of the brain neurotransmitter dopamine.

12. Abnormal psychology and mental illness

Abnormal psychology ≠ mental illness.

Abnormal psychology is not necessarily manifested as mental illness, but also includes intellectual disability, psychosomatic disease, anxiety disorder, personality disorder, etc. Abnormal psychology can only be determined by combining the three aspects of the inconsistency between psychology and environment, the lack of integrity and coordination of psychological activities, and the lack of unity of psychological activities.

13. Addiction and Dependence

Addiction ≠ dependence.

Addiction has withdrawal symptoms.

14. Antibodies and Immunoglobulins

Antibodies ≠ Immunoglobulins

All antibodies are immunoglobulins, but not all immunoglobulins are antibodies.

It can be said that antibodies move in the direction of immunoglobulins, but the reverse is not true.

15. Multiple organ failure and multiple organ failure due to chronic diseases

Multiple organ failure ≠ multiple organ failure due to chronic diseases. Multiple organ failure refers to the sequential failure of multiple organs caused by a certain critical illness, which is commonly caused by emergency abdominal surgery, severe shock, cardiac arrest, complex trauma, severe bacteremia, etc.

16. Genetic diseases and congenital diseases

Genetic disease ≠ congenital disease.

Genetic diseases are definitely congenital diseases, but congenital diseases include genetic diseases, but are not necessarily all genetic diseases.